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Biased magnetic materials in RAM applications

Ramprecht, Jörgen and Sjöberg, Daniel LU (2007) In Progress in Electromagnetics Research PIER 75. p.85-117
Abstract
The magnetization of a ferro- or ferri-magnetic material has been modeled with the Landau-Lifshitz-Gilbert (LLG) equation. In this

model demagnetization effects are included. By applying a linearized

small signal model of the LLG equation, it was found that the material

can be described by an effective permeability and with the aid of a

static external biasing field, the material can be switched between a

Lorentz-like material and a material that exhibits a magnetic

conductivity. Furthermore, the reflection coefficient for normally

impinging waves on a PEC covered with a ferro/ferri- magnetic

material, biased in the normal direction, is calculated. When the

... (More)
The magnetization of a ferro- or ferri-magnetic material has been modeled with the Landau-Lifshitz-Gilbert (LLG) equation. In this

model demagnetization effects are included. By applying a linearized

small signal model of the LLG equation, it was found that the material

can be described by an effective permeability and with the aid of a

static external biasing field, the material can be switched between a

Lorentz-like material and a material that exhibits a magnetic

conductivity. Furthermore, the reflection coefficient for normally

impinging waves on a PEC covered with a ferro/ferri- magnetic

material, biased in the normal direction, is calculated. When the

material is switched into the resonance mode, two distinct resonance

frequencies in the reflection coefficient were found, one associated

with the precession frequency of the magnetization and the other

associated with the thickness of the layer. The former of these

resonance frequencies can be controlled by the bias field and for a

bias field strength close to the saturation magnetization, where the

material starts to exhibit a magnetic conductivity, low reflection

(around -20 dB) for a quite large bandwidth (more than two decades)

can be achieved. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Progress in Electromagnetics Research PIER
volume
75
pages
85 - 117
publisher
EMW Publishing
external identifiers
  • WOS:000248081200006
  • Scopus:34547246315
ISSN
1070-4698
DOI
10.2528/PIER07052501
language
English
LU publication?
yes
id
9dc65ebc-4e98-4620-80d2-dad56d008f4a (old id 637483)
date added to LUP
2007-12-10 14:36:27
date last changed
2016-11-18 11:10:55
@misc{9dc65ebc-4e98-4620-80d2-dad56d008f4a,
  abstract     = {The magnetization of a ferro- or ferri-magnetic material has been modeled with the Landau-Lifshitz-Gilbert (LLG) equation. In this<br/><br>
model demagnetization effects are included. By applying a linearized<br/><br>
small signal model of the LLG equation, it was found that the material<br/><br>
can be described by an effective permeability and with the aid of a<br/><br>
static external biasing field, the material can be switched between a<br/><br>
Lorentz-like material and a material that exhibits a magnetic<br/><br>
conductivity. Furthermore, the reflection coefficient for normally<br/><br>
impinging waves on a PEC covered with a ferro/ferri- magnetic<br/><br>
material, biased in the normal direction, is calculated. When the<br/><br>
material is switched into the resonance mode, two distinct resonance<br/><br>
frequencies in the reflection coefficient were found, one associated<br/><br>
with the precession frequency of the magnetization and the other<br/><br>
associated with the thickness of the layer. The former of these<br/><br>
resonance frequencies can be controlled by the bias field and for a<br/><br>
bias field strength close to the saturation magnetization, where the<br/><br>
material starts to exhibit a magnetic conductivity, low reflection<br/><br>
(around -20 dB) for a quite large bandwidth (more than two decades)<br/><br>
can be achieved.},
  author       = {Ramprecht, Jörgen and Sjöberg, Daniel},
  issn         = {1070-4698},
  language     = {eng},
  pages        = {85--117},
  publisher    = {ARRAY(0x85486f0)},
  series       = {Progress in Electromagnetics Research PIER},
  title        = {Biased magnetic materials in RAM applications},
  url          = {http://dx.doi.org/10.2528/PIER07052501},
  volume       = {75},
  year         = {2007},
}